Create a in the Paddle class called 'goBig()' which resizes (or re-creates) the image and use image.drawString(String, int, int) or create a seperate image with new GreenfootImage(String, font, Color, Color) and image.drawImage(GreenfootImage, int, int); either way, finish with setImage(image). The method can be public and called from the world using a reference to the paddle object 'paddle.goBig();' (if 'paddle' is the reference name).